Prior to the present invention, as shown by Crivello, U.S. Pat. No. 3,981,897, Method for Making Certain Halonium Salt Photoinitiators, diaryliodonium salts, such as diphenyliodonium hexafluoroantimonate were prepared by effecting reaction between an intermediate diarylhalonium bisulfate and an alkylhexafluoro salt, such as diphenyliodonium hexafluoroantimonate.
In copending application Ser. No. 171,063, filed 3/21/1988, a step-wise procedure is shown for making an (octyloxyphenyl) phenyliodonium hexafluorometalloid salt which is used as a photoinitiator in non-toxic UV curable coating compositions. The procedure of Ser. No. 171,063 is directed to the initial synthesis of n-octylphenylether and the separate synthesis of a phenyliodosotosylate. The (octyloxyphenyl) phenyliodonium tosylate is synthesized in a separate reaction. Finally, the (octyloxyphenyl) phenyliodonium tosylate is metathasized with sodium hexafluoroantimonate to provide the desired (octyloxyphenyl) phenyliodonium hexafluoroantimonate salt. Although the method of Ser. No. 171,063 can provide the preferred (4-octyloxyphenyl) phenyliodonium hexafluoroantimonate salt at satisfactory yields, several steps are required which renders the procedure unsuitable for commercial production.